There are many anime out there that deal with teenagers being sent to the front lines of battle.
To name a few of the ones I have seen, there is obviously Attack on Titan, and also Mobile Suit Gundamn: Iron Blooded Orphans.
However, despite there being many anime that depict this issue of child soldiers, I would argue that few handle this topic as well as Eighty-Six.

Developed by A-1 Pictures and based off the light novel by Asato Asato, the Toshimasa Ishii directed anime begins in the Republic of San Magnolia, a country that has been at war with the Empire of Giad’s AI army, known as the Legion, for nine years.
Despite many years of war, the Republic claims to have lost none of their soldiers, due to their own mechanized, remote controlled forces.
Thing is, this is all just propaganda.
The Republic’s mechanized forces are far from remote controlled.
Their Juggernauts are actually controlled by the Colorata minority, a diverse group of people who have been stripped of all human rights by the dominant race of the Alba and forced by to fight for them, along with being forced to relocate all to the 86th District, hence the title of Eighty-Six.
With all of the Eighty-Six’s parents having been killed in the fighting, the Albans are now forcing their children to pilot their Juggernauts to fight the Legion, with Alban handlers directing them.
One of these handlers is Vladilena “Lena” Milize (Ikumi Hasegawa), who hates what has been done to the Eighty-Six, and is put in charge of the Spearhead Squadron, lead by Shinei Nouzen (Shōya Chiba), nicknamed The Undertaker.
From this point, the story unfolds, as Lena is quickly faced with the horrors the Eighty-Six have to go through on a daily basis and her own hypocrisy in how she treats them, all the while Shinei and his fellow 86 learn to deal with a handler who actually sympathizes with their plight. 

This results in numerous hard hitting moments, both on the battlefield and off, helped by the amazing animation and soundtrack by Hiroyuki Sawano and Kohta Yamamoto, all coming togethor to bring the story’s commentary on the horrors of war, nationalism, racism and child soldiers to the forefront.
Yet, there is also hopeful themes among the dark ones, which is especially apparent in the last few episodes, which were delayed due to production issues.
Despite these issues, these final few episodes were incredible, making me tear up in the penultimate episode.
Heck, even Asato Asato apparently cried at the adaptation so you know the anime did something right. 

Given the quality of these last few episodes, I really have to praise A-1 Pictures because clearly everyone involved, from the animators to the director, were passionate about this story, as proven by how they delivered the last few episode with the same quality as the rest of the anime, while having production problems.
The quality was so good that now I am even more excited for a follow up, which I hope we get.
With how amazing this anime’s story, characters, themes, direction animation and score are, if it gets a follow up, it could be up there with some of the greats.

Of all of these great features, I have to end this review by once again praising its themes.
Of all the anime I have seen with child soldiers, Eighty-Six delivers the best commentary on that.
It even trumps Attack on Titan in this regard, since Eighty-Six actually deals with the deplorable ethics of using children in war, despite their insistance to fight.
It is a theme I hope to see expanded upon whenever we get a follow up, which should happen because there is apparently enough source material to create more.
Fingers crossed that this is what happens.